Manufacturers have shown increasing interest in using paint film in lieu of spray painting for providing a decorative surface finish for parts such as automotive body parts. These parts can be manufactured using one or more of the following forming or molding processes: thermoforming, injection molding, or compression molding. In general, most processes using paint film such as thermoforming involve forming the film into a three dimensional shape and involve the use of heat and pressure. Depending upon a variety of factors including, for example, the geometry of an automobile body part, the automobile body part may or may not require an injection molding process, as long as the part is sturdy enough to facilitate the manufacturing process and is suitable for the intended end use application.
Paint films have been used for many years in a variety of applications and uses. Current products tend to lose gloss and distinctness of image (DOI) when processed, such as thermoformed, especially in high stretch areas. In many of the current paint film applications, especially high stretch applications, this deficiency has been overcome with the use of a mask to achieve high gloss and DOI for the surface finishes during thermoforming. In order to maintain the gloss and DOI, the mask must have sufficient modulus at the thermoforming temperature to maintain the smooth surface finish. In these applications, a thermoformable mask film is applied and removably adhered to the clear coat surface of the decorative sheet before the thermoforming process. In many cases, the mask is removed and discarded during the part manufacturing process, for example, before the injection molding process. The materials and manufacturing process of the mask film add significant cost to the parts produced using paint film. In addition, the use of the mask, in some cases, complicates the forming and molding processes. For example, the mask may need to be removed before an injection molding process to prevent the difficulty of removal after the parts are molded. The mask may be difficult to remove because it has been stretched substantially and becomes prone to tear and must be removed in pieces adding significant labor and possible contamination in subsequent processing. Furthermore, to date, known masked paint films have not been able to achieve a 20° gloss that is within the lower gloss range of traditional paints. Therefore, the present invention attempts to address and solve these problems.